Have you ever been to Yellowstone National Park，a national park primarily in the US state of Wyoming（怀俄明州）？At Yellowstone National Park，①． When they are heated for more than a few minutes，they will break up．
In Atlanta，the USA，there is a popular restaurant which is very special．In the restaurant，waiters no longer throw uneaten food into litter cans．Instead，②．
In America，a new activity known as"zero waste"is becoming popular．It is carried out in schools，cafes，gyms，parks，restaurants and other places．"Zero waste"activity calls on people to produce less litter．It encourages people to reuse whatever they can．
Although the idea seems a little unrealistic （不现实的），it is necessary．According to a new report，American people produce the largest amount of the litter in the world．Each person produces almost 4.6pounds of litter every day．More than half of the litter which is put into landfills is harmful． Actually，this is bad for the environment．Besides this，more landfills（填埋场） are needed．
"Nobody wants to have a landfill lying near his house，"said Jon D．Johnson from the Environmental Protection Agency，which helps to carry out"zero waste"activity．"There are not enough landfills，so we can't put all our litter into them．We should try to recycle it as much as we can．"
